The present invention is directed to an arrhythmia signalling system for an artificial heart assembly.
U.S. Pat. No. 5,674,281 to Snyder discloses an artificial heart assembly having a blood inlet conduit, a blood outlet conduit, and a pumping mechanism that pumps blood from the blood inlet conduit to the blood outlet conduit. The Snyder artificial heart assembly includes a first membrane defining a blood chamber fluidly coupled to the blood inlet conduit and the blood outlet conduit, and the pumping mechanism includes a pusher plate that makes contact with the first membrane to force blood from the blood inlet conduit to the blood outlet conduit. The Snyder artificial heart assembly also has a second membrane defining a second blood chamber fluidly coupled to a second blood inlet conduit and a second blood outlet conduit and a second pusher plate. that makes contact with the second membrane to force blood from the second blood inlet conduit to the second blood outlet conduit.
U.S. Pat. No. 5,728,154 to Crossett, et al. discloses an artificial heart assembly that has a structure similar to the artificial heart assembly described above in connection with the Snyder patent. The Crosset, et al. patent also discloses a communications system that includes an external transceiver located external to Apr. 24, 2000 a subject and an internal transceiver that is implanted beneath the skin of a subject. The internal transceiver is provided with an internal coil.
U.S. Pat. No. 5,751,125 to Weiss discloses an artificial heart assembly, which is provided either as a total artificial heart or as a ventricular assist device, having a sensorless motor and a circuit for reversibly driving the sensorless motor.
U.S. Pat. No. 5,630,836 to Prem, et al. discloses a transcutaneous energy and data transmission apparatus for a cardiac assist device such as an artificial heart or ventricular assist device. The transmission apparatus has an external coupler in the form of a tuned circuit with an induction coil and an internal coupler which together act as an air-core transformer. The transmission apparatus has a DC power supply and a power converter that are coupled to the external coupler. The power converter converts electrical current from the DC power supply into high-frequency AC. The transmission apparatus has a voltage regulator coupled to the internal coupler.
In one aspect, the invention is directed to an artificial heart assembly having a blood inlet conduit adapted to be implanted within a subject, a blood outlet conduit adapted to be implanted within the subject, a pumping mechanism implanted within the subject that pumps blood from the blood inlet conduit to the blood outlet conduit, and a motor coupled to drive the pumping mechanism. The artificial heart apparatus has a power source and a control circuit operatively coupled to cause the motor to drive the pumping mechanism in a regular mode when the power source has a relatively high charge level and in an irregular mode when the power source has a relatively low charge level so that the subject can feel when the pumping mechanism is being driven in the irregular mode and thus know that the power source has the relatively low charge level.
The control circuit may cause the motor to drive the pumping mechanism in a first direction for a first time period and in a second direction for a second time period, and the control circuit may cause the pumping mechanism not to be substantially moved during a variable delay period between the first time period and the second time period, with the variable delay period having a variable duration which depends on the charge level of the power source. The variable delay period may have a relatively long duration when the power source has a relatively low charge level and a relatively short duration when the power source has a relatively high charge level.
The artificial heart apparatus may include a second power source, and the control circuit may cause the motor to drive the pumping mechanism in the irregular mode when neither of the power sources generates a voltage above a threshold voltage.
The artificial heart apparatus may also be provided with a membrane defining a blood chamber fluidly coupled to the blood inlet conduit and the blood outlet conduit, and the pumping mechanism may be provided in the form of a pusher member that makes contact with the membrane to force blood from the blood inlet conduit to the blood outlet conduit.
In another aspect, the invention is directed to an artificial heart assembly having a blood inlet conduit, a blood outlet conduit, a pumping mechanism that is adapted to pump blood from the blood inlet conduit to the blood outlet conduit, and a motor coupled to drive the pumping mechanism. The artificial heart assembly is also provided with a control circuit operatively coupled to drive the motor, the control circuit causing the motor to drive the pumping mechanism in a regular mode in response to a condition relating to the artificial heart assembly being absent and in an irregular mode in response to the condition being present so that the subject can feel when the pumping mechanism is being driven in the irregular mode and thus know that the condition is present.
The control circuit, which may include a microprocessor, a program memory, a computer program stored in the program memory, and a driver circuit, may cause the motor to drive the pumping mechanism in a first direction for a first time period and in a second direction for a second time period. The control circuit may cause the pumping mechanism not to be substantially moved during a variable delay period between the first time period and the second time, with the variable delay period having a variable duration which depends on whether the condition is present or absent. The variable delay period may have a relatively long duration when the condition is present and a relatively short duration when the condition is absent.
The invention is also directed to a method of operating an artificial heart assembly having a pumping mechanism that is adapted to pump blood from a blood inlet conduit to a blood outlet conduit. The method includes: determining whether a condition relating to the artificial heart assembly is present, if the condition relating to the artificial heart assembly is present, then driving the pumping mechanism in an irregular mode, and if the condition relating to the artificial heart assembly is not present, then driving the pumping mechanism in a regular mode.
The method may include determining whether a power source generates a voltage lower than a normal operating voltage, driving the pumping mechanism in the irregular mode if the power source generates a voltage lower than the normal operating voltage, and driving the pumping mechanism in the regular mode if the power source does not generate a voltage lower than the normal operating voltage.
The features and advantages of the present invention will be apparent to those of ordinary skill in the art in view of the detailed description of the preferred embodiment, which is made with reference to the drawings, a brief description of which is provided below.